Pump



Feb. 22, 1949. E. A. CUNY 2,462,725

' PUMP Filed Dec. 18, 1945 4 Shepts-Sheet 1 MXWM Feb. 22, 1949. E. A. cuNY 2,462,725

PUMP Filed Dec. 18, 1945 4 Sheets-Sheet 2 J- Jfi v If I 1 42,111,: I I

" 'm YX$ Jazz E. A. CUNY Feb. 22, 1949.

PUMP

4 Sheets-Sheet 3 Filed Dec. 18, 1945 BY i A rroe/v'y E. A. CUNY Feb. 22, 1949.

4 Sheets-Sheet 4 PUMP Filed Dec. 18, 1945 r y [m MUM 4m f w M 9' I w 4 w ////////4 Patented Feb. 22, 1949 PUMP Ernest A. Cuny, New York, N. Y., assignor to Cuny Engineering Inc., a corporation of New Hampshire Application December 18, 1945, Serial No. 635,645 12 Claims. (Cl. 103-161) The invention here disclosed relates to fluid displacement devices in the nature of rotary pumps.

Objects of the invention are to provide a pump of this type which will be of simple, practical construction, efiicient in operation for either pressure or high vacuum, consist of but few rugged parts and which with all its advantages may be produced at relatively low cost.

Special objects of the invention are to balance the operating parts to accomplish smooth, quiet, easy operation and to avoid any improper loading of the pumping elements.

A related object is to effect balance of pressures in a way to maintain a floating operation of the rotor and the full lubrication of all operating parts.

Further special objects are to provide for adjustment of both or either volume and pressure and to enable accomplishment of such adjustment or adjustments while the machine is in operation.

Another special object is to provide an autov matic pressure relief and return of practical design and incorporated within the pump structure, thus avoiding use of the usual return lines or the like.

Another special object is to provide an automatic pressure relief and return of practical design and incorporated within the pump structures, thus avoiding use of the usual return lines or the like.

Other objects are to provide the pump structure in the form of a unit adapted to be operated as such or, if desired, to be incorporated in a special case and in conjunction with the latter feature, to provide ample intake and screening facilities, the possibility of operating in either direction of rotation and the provision of an effective, self-adjusting rotary seal.

Other desirable objects and the novel features through which the purposes of the invention are attained are set forth or will appear in the course of the following specification.

The drawings accompanying and forming part of the specification illustrate several of the present practical embodiments of the invention but it is to be understood that structure and operation may be modified and changed as regards the immediate disclosure, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawing is a front elevation of one of the pumps with the cap at the center removed to show the stroke adjusting mechanism and with certain parts broken and appearing in section;

Fig. 2 is a broken vertical sectional view on substantially the plane of line 2--2 of Fig. 1;

Fig. 3 is a broken sectional detail taken on a horizontal plane to show the other two pistons not appearing in Fig. 2;

Figs. 4 and 5 are broken front and vertical sectional views, respectively, of another form. or stroke setting mechanism;

Fig. 6 is a broken vertical sectional view of a form of automatic, pressure regulated, stroke setting mechanism;

Fig. '7 is a vertical sectional view as on substantially the plane of line l-l of Fig. 2;

Fig. 8 is a top plan view of the liner constituting the cylindrical pump chamber and provided with the pressure relieving and balancing passages;

Fig. 9 is a part broken sectional end elevation of a modified form of rotor and piston combination;

Fig. 10 is a vertical sectional view of another, multiple piston form of the pump, this view appearingas taken on substantially the plane oi line lE-IB of Fi 11;

Fig. 11 is a vertical sectional view 'as on substantially the plane of line Il--ll of Fig. 10; v Fig. 12 is a horizontal sectional view as on substantially the plane of line I2-l2 of Fig. 10'

but showing this form of the pump as shaft driven instead of fluid actuated as in Figs. 10 andll;

Fig. 13 is a plan view showing the motor type of pump illustrated in Figs. 10 and 11 directly coupled to operate a smaller chemical proportioning or metering pump.

The form of the invention first illustrated comprises an annular cylindrical form of rotor le having four radially extending pumping cylinder passages IS in which operate pistons ll having rectangular extending pins l8 at the inner ends of the same pivotally engaged in short connecting links l9 which in turn are pivotally engaged over a relatively stationary crank pin 26.

As best shown in Figs. 2, 3, 6 and '7, the connecting links I! are disposed in side-by-side relation on the crank pin 20 and the pins 88 at the inner ends of the piston are formed as integral rigid extensions of the pistons, two of them, as in Fig. 2, projecting laterally far enough to reach only the two innermost links and the other two, as in Fig. 3, reaching past the intermediate links IS into engagement with the outermost or end links. In this manner all four pistons are freely reciprocated in the operation of the rotor and to an extent determined by the relative eccentricity of the crank pin 2a.

In Figs. 1 and 2 the crank pin 20 is shown carried by and projecting from a. cross slide 2! shiftable in a radial guide opening 22 in the stationary hub portion 23 of the pump.

In these views adjustment of the pin carrying slide 2| is effected by turning a disc 24 rotatably supported in the hub 23 over the slide, as by means of a spanner wrench or like tool, said disc having in itsinner face an eccentric groove 25 receiving the pin 26 on the slide.

The stroke adjusting disc 24 is secured in set position in the Figs. 1 and 2 construction by tapered screw 21 entered through the outer face of the disc between the ends of a split expansion ring 28 seated in annular groove 29 in the disc and having a conical wedging engagement in the wall of the hub at 38. This provides a simple, secure means for locking up the disc in any position ofrotary adjustment between zero and maximum eccentricity of the crank pin 20.

These adjustments may be made while the machine is in operation. .Normal'y theseparts are covered and protected by screw cap 3 I removably engaged over the hub 23. I

Figs. 4 and 5 illustrate a modification of the stroke or volume adjusting means embodying the mounting of the crank pin 20 on a yoke 32 having its arms slidingly engaged over a dia-,

metrical screw stud33 fixed in the hub portion 2311 with a micrometer screw 34 on the stud between the arms of the yoke having an index line 35 to register on a stationary scale 36 graduated in volume or other units. This micrometer screw is shown as secured in the position of adjustment by a springdetent 31.

Automatic adjustment of the pumping stroke and hence efifective displacement, is accomplished in the Fig. 6 embodiment by constructing the cross slide carrying the crank pin 20 as a piston 38 operating in a transverse cylindrical chamber 39 in the hub and subjected to the developed pumping pressure through the porting indicated in dotted lines at 4|]. A screw plug 4| closing the end of the pressure cylinder over the head of the piston carries a stop projection 42 limiting the out-stroke or maximum displacement position of this control piston and a screw plug 43 in the opposite end of the piston chamber provides an adjustable abutment for the spring 44 thrusting the piston toward the stop 42.

By adjustment of the stop screw plug 4| the maximum displacement position of control piston 38 may be set to determine the maximum pumping stroke of the pistons l1 and by adjustment of the other screw plug 43 the tension of spring 44 may be adjusted to determine the maximum pressure to be developed by the pump.

The control piston '38 is shown slotted in the outer side at 45 to slide over a transverse guide rib 46.

The cylindrical pumping chamber in which the rotor operates is shown as made up of outer and inner cylindrical members 41, 48, and end plates 49, 50, doweled together at 5|, 52 and held by screws 53.

This, with the enclosed parts constitutes a substantially complete pump unit which may be used as such or which may be embodied within a suitable pump casing to constitute, in eflect, a removable and replaceable pump unit.

In the illustration the pumping. unit is shown enclosedwithin a pump casing made up of a body section 54 carrying the shaft bearing and necessary connections for piping and a complementary cover section 55, these receiving the ends of the dowels 5|, 52, Fig. 2, and being secured together by bolts or screws 56.

This arrangement provides opportunity for a large annular intake chamber 51 completely about the enclosed pump unit and the provision of a cylindrical screen 58 carried by the perforate annular wall or flange 59 projecting inwardly 4 from the cover; about the pump unit and making sealing engagement at its inner edge with a gasket or packing 66 against the back of the intake chamber. This intake chamber is shown in Fig. 7 as having inlets 6| in both sides of the same, either one or both of-which may be used, one being closed, as by screw plug, when only one is being used.

To provide for operation with rotation in either direction, the outer ring 47 of the pump unit is, shown as equipped with an arcuate manifold extension 62 having an outlet port 63 in the back to register with an upwardly extending passage 64 in the-casing, Fig. 2, and branches 65, 66, extending to said outlet port from the radial, inwardly extending passages 61-, 68.

The branch passages 65, 66, have plug valves 69, 70, therein which, as shown in Fig. '7, may be set to closeoff one branch passage, such as 65, from the outlet 63 and to leave the other passage, such as 66, opened up to the outlet 63.

The branch passages 65, 66, further have portions ll, 12, opening through the front of the manifold into the screened inner port of the intake chamber 51 and adapted one or the other to be closed asby a screw plug 13.

In the illustration, Fig. 7, where the rotor is turning counter-clockwise as indicated by the arrow, the port ll at the left side of the manifold is the intake port and so is left open or uncovered, while port 12 at the opposite side forms part of the outlet passage and so is closed by the ping 13.

It will be clear from Fig. 7 that for rotation in clockwise direction the parts would be reversed, that is, the port ll would be closed by plug 13 and port 12 left open to serve as an intake and the valve 70 would be closed and the valve 69 opened to the discharge outlet 63.

To make the pump self-compensating for pressure the discharge passage 64 is shown as opening at 14 into a pressure chamber 15 closed at one end by a spring loaded ball valve 16 and at the opposite end by a piston 11 operating in cylinder 18 against the pressure of spring 19. The tension of this spring is adjustableby means of abutment screw 88 and this screw is shown as-carrying a screw stud adjustable to serve as a stop for the piston to prevent full collapsing of the spring 19.

The ball valve 16 is held to its seat by a spring- 82, the tension of which is adjustable by means of abutment screw 83. The setting of this tension spring determines the pressure at which the ball valve will open to relieve pressure back through passage 84 back into the annular intake chamber 51.

The relief ports 8|, asshown'in Figs. 2 and 7, open into a, surrounding space 85 connected with the discharge outlet 86 in the top of the pump casing. a The inner ring 48 is secured by a press fit or otherwise as a liner within' the pump body 41, and is formed with radial ports 81, 88, in line with the radial passages .61, 68, for purposes.

To avoid any locking effect at either the intake or the discharge side of the pump,- segmental grooves 89, 98, are formed in the inner face of the liner extending from a relatively short short change-over space 92 at the bottom.. These grooves allow for full intake and discharge ac.-

tion of the pistons without binding or locking at any points in the cycle of operation.

To balance pressure on opposite sides of the intake and exhaust rotor and thus offset any binding tendency which might result from development of high pressures, narrower compensation grooves 93, 94 are provided on the inside of the liner at opposite sides of the intake and discharge grooves 89, 90, and of substantially the same full arcuate extent. These compensation grooves are cross connected with the opposed pressure grooves 09, 90. Thus the grooves 93, 94, at the left in Figs. 7 and 8,

are connected together in parallel by through ports 95 and transverse groove 96 in the outer surface of the liner and by arcuate groove 91 and through port 98 with the pressure groove 90; and the compensation grooves 94 at the right are connected together by through ports 99 and transverse groove I09 with the opposed interior pressure groove 89 by exterior arcuate groove IOI and through port I02.

In the particular example illustrated, the main internal groove 89 is an intake or low pressure groove and this is connected by port I02, passages I I00, and ports 99 with the narrow compensating grooves 9% at opposite sides of the other main groove 90, which is the discharge or high pressure groove. In reverse effect this high pressure groove is connected by port 98, passages 91, 96 and ports 95 with the narrow compensating grooves 93, 9d, at opposite sides of low pressure groove 89. Thus the low pressure groove 89 has segments of high pressure 93 at opposite sides of it and the high pressure groove 90 has segments of low pressure St at opposite sides of it.

The narrow compensating grooves may be substantially half the width of the wider pressure grooves with which they are associated. This accomplishes substantially even balance of presbe spring operated in the return or retractive wheel to constitute the machine motor as well sure on opposite sides of the rotor, leading to smooth. easy, free, frictionless operation of the rotor and assuring a full, complete film of lubricant over the rotor surface. With proper close running fit of the rotor within the liner, the film of lubricant thus maintained during operation of the pump efiects an efficient seal of the rotor within its working chamber.

With a further view to maintaining accurate alignment of the rotor within the pump chamber, the rotor is shown constructed with a hub I03 at the back or closed side, journaled in a bearing I09 in the end plate 49 and with a hub extension I05 at the front or open side journaled on a bearing I06 on the other or front end plate 50.

The drive of the pump is effected in the illustration by a drive shaft I07 journaled in a bearing I08 carried by a flange nut I08 screwed into the end of a bearing housing I I0 'on the back of the pump casing, the inner end of this shaft entering the hub I03 of the rotor and carrying a drive pin I I I entering anotch in the rotor hub.

This construction provides a readily separable drive connection or coupling between the shaft I01 and the pump unit removably seated in the pump housing.

To seal the drive .shaft in its coupled engagement with the pump unit the shaft bearing I08 is finished at-the inside as a lap joint with the sealing flange I I2 which while loose on the shaft is sealed to the shaft by packing H3 held by a cup H4 under pressure of spring H5 backed up by abutment washer H6, the latter in abutment with the cross pin I I I.

This provides a compensating, self-adjusting, spring tensioned rotary seal between the rotating shaft and the housing and bearing for the same.

The pump piston, instead of being positively connected with the actuating crank pin 20, may

as a pump. i

In this particular embodiment of the invention the pistons I20, as in the copending patent ap plication Serial No. 539,345, filed June 8th, 1944, now abandoned, have connecting links or straps I2I at their inner endspivotally engaged about a bushing I22 carried by a hollow crank pin I29 on one end plate I24 and the rotor has a hub portion I25 freely journaled on a pivot stud I29 carried by the back wall or opposed end plate I2! of the combined motor and pump housing.

In this construction the bucket forming cylinders and pistons automatically clear themselves of the water or other impelling fluid as they rotate past the point I28 separating the fluid inlet and outlet sides I29, I30, of the combined motor and pump casing.

In passing over the port I3I the pistons I29,

ion in their retractive movement draw in any chemical or other fluid that the pump may be intended to deliver into the discharge stream.

While the pressure balancing grooves first disoiosed may be employed in this motor-pump combination, for simplicity there has been shown a single relief groove I32 extending from the point I33 to the intake passage I29, and a single 40 relief groove I extending from the discharge passage I30 back to the arcuate sealing section I33.

The stroke of the pistons is adjustable in the form of the invention under consideration by rotative movement of the front cover plate I29 and which can be secured in its various positions of adjustment by the screw flange ring I39.

Fig. 12 illustrates a modification of the motorpump combination shown in Fig. 10 by the provision of the rotor with a shaft extension I36 by which it may be driven to operate as a combination pump to draw in water or other liquid or fluid at'the inlet I29 as well as chemical or other liquid or fluid at the smaller inlet I3I.

Fig. 13 illustrates an adaptation of the water motor type of pump I31 shown in Fig. 10 applied to the direct driving of a smaller chemical pump I38 like that first disclosed in Figs. 1 and 2, having an inlet connection I39 and an outlet connection I40 discharging into the outlet side I30 of the combination water motor pump I31.

The balance grooves at opposite sides of each pressure groove present substantially equal area and opposite pressure to the rotor as the socalled pressure groove with which they are related and hence draw out or spread a film of the liquid being pumped, thus to float the rotor in a pressure balanced, substantially frictionless, full size bearing, where the driving force will be practically only that required to rotate it. This full sealing effect on the rotor makes the machine efilcient as a high vacuum pump.

What is claimed is:

l.v A pump comprising a pump cylinder. a

rotor having a close running fit in said cylinder and external means for effecting rotation of the same, said rotor having a radial piston cylinder open at the outer end to said pump cylinder, a piston operable in said piston cylinder, acrank pin eccentrically related to said rotor and connected with said piston for effecting reciprocation of said piston in the rotation of said rotor, said pump cylinder having low and high pressure grooves extending arcuately around opposite sides of the same between the points of maximum and minimum displacement positions of the piston and said pump cylinder having an inlet passage opening into the low pressure groove and a discharge passage extending from the high pressure groove, and balancing grooves at the sides of and of substantially the same longitudinal extent as the pressure grooves, said balancing grooves being connected one at the low pressure side across to the high pressure groove and one at the high pressure side across to the low pressure groove, -said balancing grooves being connected and arranged in pairs disposed with the grooves of each pair along opposite .sides of said pressure grooves, the wall of said pump cylinder being provided by a liner, saidbalancing grooves being formed in the inner face of said liner and said cross connections being provided by holes through and grooves in the outer face of said liner.

2. A pump comprising a pump cylinder, a rotor having a close running fit in said cylinder and external means for efiecting rotation of the same, said rotor having a radial piston cylinder open at the outer end to said pump cylinder, a piston operable in said piston cylinder, a crank pin eccentrically related to said rotor and connected with said piston for efiecting reciprocation of said piston in the rotation of said rotor, said pump cylinder having low and high pressure grooves extending arcuately around opposite sides of the same between the points of maximum and minimum displacement positions of the piston and said pump cylinder having an inlet passage opening into the low pressure groove and a discharge passage extending from the high pressure groove, and balancing grooves at the sides of and of substantially the same longitudinal extent as the pressure grooves, said balancing grooves being connected one at the low pressure side across to the high pressure groove and one at the high pressure side across to the low pressure groove,'the wall of said pump cylinder being provided by a liner,.said balancinggrooves being formed in the inner face of said liner and said cross connections extending through and along the outer face of said liner.

3. A pump comprising a pump cylinder, a rotor having a close running fit in said cylinder and external means for effecting rotation of the same, said rotor having a radial piston cylinder open at the outer end to said pump cylinder, a piston operable in said piston cylinder, a crank pin eccentrically related to said rotor and connected with said piston for effecting reciprocation of said piston in the rotation of said rotor, said pumpv cylinder having low and high pressure grooves extending arcuately around opposite sides of the same between the points of maximum and minimum displacement positions of the piston and said pump cylinder having an inlet passage opening into the low pressure groove and a discharge passage extending from the high pressure groove, and means for effecting reverse connection of said passages in respect to said low and high pressure grooves forenabllng operation of said pump' rotor in either direction; i

4. A pump comprising a pump cylinder having.

an intake chamber, a rotor having a close running fit in said cylinder and external means for eifectin rotation of the-same, said rotor having a radia piston cylinder open at the outer end to said pump cylinder, a piston operable in said piston cylinder, a crank pin eccentrically related. to said rotor and connected with 'said piston for efiecting reciprocation of said piston in the rota-' sure groove and a discharge passage extending from the high pressure groove, and means for effecting reverse connection of said passages in respect to said low and high pressure grooves for enabling operation of said pump rotor in either direction and including a manifold in said intake chamber, having an outlet and branches extending from said passages to said outlet, valves to close either branch and open the other one in respect to said outlet and closures for said'b'ranches removable either one to open whichever passage is connected with the closed branch to said intake chamber.

5. A pump comprising a pump cylinder having an intake chamber, a rotor having a close running fit in said cylinder and external means for effecting rotation of the same, said rotor having a radial piston cylinder open at the outer end to said pump cylinder, a piston operable in said piston cylinder, a crank pin eccentrically related to said rotor and connected with said piston for efiecting'reciprocation of saidpiston in the rota- 40 tion of said rotor, said pump cylinder having low and high pressure grooves extending arcuately around opposite sides of the same between the points of maximum and minimum displacement positions of the piston and said pump cylinder having an inlet passage opening into the low pressure groove and a discharge passage extending from the high pressure groove, and means for effecting reverse connection of said passages in respect to said low and high pressure grooves for enabling operation of said pump rotor in either direction and including a manifold in said intake chamber, having an outlet and branches extending from said passages to said outlet, valves ,to close either branch and open the other one in respect to said outlet and closures for said branches removable either one to open whichever passage is connected with the closed branch to said intake chamber, said pump casing having an outlet chamber and pressure ope'rated valve means controlling fiow from said manifold outlet to said 7 outlet chamber.

' said rotor having a radial piston cylinder open at the outer end to said pump cylinder; a piston operable in said piston cylinder, a crank pin eccentrically related to said rotor and connected with said piston for effecting reciprocation of said piston in the rotation of said rotor, said pump cylinder having inlet and outlet passages, an outlet chamber in said pump cylinder connected with the outlet passage and having a pressure operated check valve at one end and a pressure opened discharge valve at the opposite. end and a pressure return connection from the outlet side of said check valve back to said inlet passage.

7. A pump comprising a pump cylinder, a rotor having a close running flt in said cylinder and external means for effecting rotation of the same, said rotor having a radial piston cylinder open at the outer end to said pump cylinder, a piston operable in said piston cylinder, a crank pin eccentrically related to said rotor and connected with said piston for eifecting reciprocation of said piston in the rotation of said rotor, said pump cylinder having inlet and outlet passages, an outlet chamber in said pumps cylinder connected with the outlet passage and having a pressure operated check valve at one end and a pressure opened discharge valve at the opposite end and a pressure return connection from the outlet side of said check valve back to said inlet passage, means for predetermining the opening pressure of said check valve and means for setting the relative eccentricity of said crank pin.

8. A pump comprising a pump casing having an inlet chamber and an outlet chamber, said outlet chamber having a return passage open to said inlet chamber and a spring closed check valve normally closing said passage, a pump cylinder in said casing having an inlet port open to said inlet chamber and an outlet port open to said outlet chamber, said casing having a delivery passage extending from said outlet chamber, a spring closed valve controlling flow from said outlet chamber to said delivery passage, a rotor operating in said pump cylinder and having external means for eifecting rotation of the same, said rotor being provided with a radial piston cylinder open at the outer end to said pump cylinder and a crank pin eccentrically related to said rotor and connected to operate said piston in the rotation of said rotor.

9. A pump comprising a pump casing having an inlet chamber and an outlet chamber, said outlet chamber having a return passage open to said inlet chamber and a spring closed check valve normally closing said passage, a pump cylinder in said casing having an inlet port open to said inlet chamber and an outlet port open to said outlet chamber, said casing having a delivery passage extending from said outlet chamber, a spring closed valve controlling flow from said outlet chamber to said delivery passage, a rotor operating in said pump cylinder and having external means for effecting rotation of the same, said rotor being provided with a radial piston cylinder open at the outer end to said pump cylinder and a crank pin eccentrically related to said rotor and connected to operate said piston in the rotation of said rotor, said valves being located at opposite ends of said outlet chamber, the outlet passage opening into the intermediate portion of said outlet chamber between said valves and regulatable means for determining the spring closing tension on said valves.

10. A pump comprising a. casing having a pump cylinder, a rotor having a close running flt in said cylinder and external means for effecting rotation of the same, said rotor having radial piston cylinders open at the outer ends to said pump cylinder, pistons operating in said piston cylinders, a crank pin at the inner ends of said piston cylinders, links pivotally connecting said pistons with said crank pin, means for supporting and setting said crank pin in eccentric relation to said rotor, said pump cylinder having inlet and outlet ports in communication with the open outer ends of the piston cylinders in the rotation of the rotor, said means forsupporting and setting said crank pin including a supportior said crank pin shiftable radially in respect to the center of rotation of the rotor and means for shifting and securing said support including a rotatably adjustable eccentric rotatably mounted on said casing and connected with said support and means on the pump casing for locking said eccentn'c in adjusted relation.

11. A pump comprising a casing having a pump cylinder, a rotor having a close running fit in said cylinder and having radial piston cylinders open at the outer ends to said pump cylinder, pistons operating in said piston cylinders, a crank pin at the inner ends of said piston cylinders, links pivotally connecting said pistons with said crank pin,

' means for supporting and setting said crank pin in eccentric relation to said rotor, said pump cylinder having inlet and outlet ports in communication with the open outer ends of the piston cylinders in the rotation of the rotor, said means for supporting and setting said crank pin including a support for said crank pin shiftable radially in respect to the center of rotation of the rotor and means for shifting and securing said support including an adjustably tensioned piston operable in the pump casing and a pressure. connection from the pump cylinder for applying pressure to said adjustably tensioned piston.

12. A pump comprising a casing having a pump cylinder, a rotor provided with means for rotating same and having a close running lit in said cylinder, said rotor having a radial piston cylinder open at the outer end to said pump cylinder, a piston operable in said piston cylinder, a crank pin eccentrically related to said rotor and connected to said piston for effecting reciprocation of the same in the rotation of said rotor, a liner forming the wall of said pump cylinder and having high and low pressure grooves in the inner surface of the same extending arcuately around opposite sides of the cylinder between points of maximum and minimum displacement positions of the piston, passages extending through said liner into said low and high pressure grooves to form inlet and discharge passages, balancing grooves in the inner face of the liner at opposite sides of said low and high pressure grooves, a cross channel in the outer face of the liner connecting the balancing grooves at opposite sides of the low pressure groove and a channel in the outer face of the liner extending from said cross channel to the high pressure groove, a cross chan nel in the outer face of the liner connecting the balancing grooves at opposite sides of the high pressure groove and a channel in the outer face of the liner extending from said last mentioned cross channel to said low pressure groove.

ERNEST A. CUNY.

REFERENCES CITED The following references are of record in the flle'of this patent:

. UNITED STATES PATENTS Number Name Date 1,612,888 Schneggenburger Jan. 4, 1927 2,221,501 Waite Nov. 12, 1940 2,328,717 Glasner Sept. '7, 1943 2,393,128 Temple Jan. 15, 1946 FOREIGN PATENTS Number Coimtry Date 375,985 Germany May 22, 1923 

